Certain problems are encountered when pouring a liquid fuel, such as gasoline, from a container into a tank associated with an internal combustion engine, as used in a lawnmower, chainsaw, snowmobile, vehicle, or the like. One problem is overflow or spillage of the gasoline which can provide a health and safety hazard. In addition, escape of vapor from the tank to the atmosphere as the fuel is poured into the tank also provides a health, safety, and environmental risk.
To overcome these problems, it has been proposed in the past to incorporate a pour spout with the fuel can or container which automatically shuts off flow of fuel when the tank is filled. Pour spouts, as used in the past, have included a fuel conduit and a sleeve, which is threaded to the neck of the fuel container, is mounted for sliding movement within the fuel conduit. The outer end of the sleeve carries a valve or closure which closes off the fuel conduit. In devices of this type, the closure is spring biased to a closed position and a collar or abutment is mounted on the outer surface of the fuel conduit and is adapted to engage the upper edge of the tank neck when the spout is introduced into the neck, so that continued force applied through the container will move the sleeve axially relative to the fluid conduit to open the closure and permit the flow of fuel into the tank.
In one form of common pour spout the gasoline vapor and air within the tank is vented upwardly through the fuel conduit to the container, but this type of venting provides an intermittent flow of fuel in which the fuel flow is in slugs, as opposed to a continuous smooth flow.
It has also been proposed to include a vent tube in the pour spout, so that the vapor within tank will be vented through the vent tube to the container and thus provide a smoother flow of fuel.
Fuel tanks, as used on internal combustion engines have necks of various configurations and depths. If the neck is shallow, having a relatively short axial length, the lower end of the fuel conduit and vent tube of the pour spout may be located a substantial distance from the top of the tank. The flow of fuel through the spout will be terminated when the fuel level reaches the inlet of the vent tube and in this case, with the inlet of the vent tube being located a substantial distance beneath the upper end of the tank, the tank cannot be completely filled. On the other hand, if the tank neck is relatively deep, having a long axial length, the lower end of the spout will not extend into the tank with the result that overflow can occur. Thus, pour spouts, as used in the past, have not been capable of accommodating tanks with various neck configurations.
Certain pour spouts, as used in the past, have included a closure for sealing the vent tube when the fuel conduit is closed to prevent foreign material from entering the vent tube during periods of storage. If the fuel container is subjected to an elevated temperature during storage, a pressure buildup can occur in the container and when the spout is subsequently introduced into the fuel tank, a rapid and uncontrolled discharge of fuel can occur. To eliminate this problem, some pour spouts have incorporated a provision for enabling the vent passage to be manually relieved prior to introducing the spout into the tank neck. However, manual relief of the vent tube can cause the discharge of fuel and vapor into the atmosphere and provide a safety and health hazard.
Another problem involves the entry of foreign particulate material such as dirt, sand or the like into the sliding interface or clearance formed between the sleeve and the conduit. Accumulation of such foreign material may hinder the sliding movement between the conduit and sleeve thus impeding proper operation of the spout, and may also cause premature failure of the spout.